Separated from the mainland by the Strait of Canso, it is 110 mi (175
km) long and up to 75 mi (120 km) wide, with an area of 3,981
sq mi (10,311 sq km). It contains the Bras d'Or salt lakes. Originally
called Île Royale as a French colony, it later took the name of its
eastern cape, probably the first land visited by John Cabot on his
1497–98 voyage and probably named by Basque fishermen from
Cap Breton, France. It was ceded to the British by the 1763 Treaty of
Paris and joined to Nova Scotia. In 1784 it became a separate
British crown colony, but it was rejoined to Nova Scotia in 1820. In
1955 the island was linked to the mainland by a causeway. Cape
Breton Highlands National Park was established in 1936.
(Source: Britannica Online)